Visual search using realistic camouflage: countershading is highly effective at deterring search.
Visual search using realistic camouflage: countershading is highly effective at deterring search.
复制标题
使用逼真的伪装进行视觉搜索：反阴影对于阻止搜索非常有效。
DOI：
10.1167/15.12.968
复制
发表时间：
2015
影响因子：
1.8
通讯作者：
Penacchio O
中科院分区：
文献类型：
--
作者：
Penacchio O
动物王国中最普遍的着色模式之一是反阴影，这是一种颜色渐变，其中面对较高光强度的身体部位较暗。反阴影可以帮助平衡定向光产生的阴影，从而减少通过阴影形状进行的 3D 对象识别。有证据表明，其他动物以及人类都可以从阴影中获取形状信息。在这里，我们通过实验评估了优化反阴影伪装对检测速度和准确性的影响，以探讨是否需要微调反阴影以实现隐秘。我们使用了一个计算 3D 世界，其中包括生态逼真的照明模式。我们用椭圆形“干扰器”叶子和椭圆体目标物体定义了 3D 场景。场景使用不同类型的照明进行渲染，目标物体被赋予不同程度的伪装：完全没有，针对场景的光分布和空间中的目标方向进行优化的反阴影图案，或者针对不同的光源进行优化。参与者 (N= 12) 被要求尽快检测场景中的目标 3D 对象。结果表明，反阴影伪装对检测率和准确率有非常显着的影响。反阴影图案偏离实际照明条件和目标物体方向的最佳图案的程度对检测性能有很大影响。该实验表明，适当的反阴影伪装会降低检测率和准确性，从而强烈干扰视觉搜索。基于类似刺激的鸟类野外捕食实验显示出类似的效果。总而言之，这表明反阴影阻碍了跨物种的有效视觉搜索并降低了能见度，从而提高了采用反阴影的猎物的生存率。
One of the most widespread patterns of colouration in the animal kingdom is countershading, a gradation of colour in which body parts that face a higher light intensity are darker. Countershading may help counterbalance the shadowing created by directional light, and, hence, reduce 3D object recognition via shape-from-shading. There is evidence that other animals, as well as humans, derive information on shape from shading. Here, we assessed experimentally the effect of optimising countershading camouflage on detection speed and accuracy, to explore whether countershading needs to be fine-tuned to achieve crypsis. We used a computational 3D world that included ecologically realistic lighting patterns. We defined 3D scenes with elliptical ‘distractor’leaves and an ellipsoid target object. The scenes were rendered with different types of illumination and the target objects were endowed with different levels of camouflage: none at all, a countershading pattern optimized for the light distribution of the scene and target orientation in space, or optimized for a different illuminant. Participants (N= 12) were asked to detect the target 3D object in the scene as fast as possible. The results showed a very significant effect of countershading camouflage on detection rate and accuracy. The extent to which the countershading pattern departed from the optimal pattern for the actual lighting condition and orientation of the target object had a strong effect on detection performance. This experiment showed that appropriate countershading camouflage strongly interferes with visual search by decreasing detection rate and accuracy. A field predation experiment using birds, based on similar stimuli, showed similar effects. Taken together, this suggests that countershading obstructs efficient visual search across species and reduces visibility, thus enhancing survival in prey animals that adopt it.